High heterogeneity, mixed infections and new genotypes in human congenital toxoplasmosis cases in the mega-metropolis of Central Mexico

Mexico presents high prevalence of Toxoplasma gondii infection, including the congenital form, but there are few data about the genetic diversity of the parasite, so we attempted parasite isolation and genotyping in nine mother/children pairs with congenital toxoplasmosis (CT), living in the Valley of Mexico, who were part of a 30 cases cohort that started 12 years ago. They were recruited through research projects which included pre- and postnatal screening of congenital infections or directly CT, and cases referred to INP for management because they had clinical abnormalities. Genotyping was performed by PCR-RFLP of SAG1, SAG2, SAG3, BTUB GRA6, c22-8, c29-2, L358, PK1 and Apico markers, followed by sequencing. Sixty seven percent of samples were typed for the SAG3 locus, 39% for Apico and 33% for BTUB, while Alt. SAG2, GRA6 and c29-2 types could be labelled in less cases. Type I alleles predominated, followed by II and III. We isolated the first strain obtained from humans in Mexico and found three genotypes not previously found in the world. The presence of ToxoDB#10 clonal type was documented in one pair, as well as mixed infections in five mothers. No relation of genotype or parasite load with clinical signs was found. In conclusion, we encountered great genetic diversity and mixed T. gondii infections among mother/children pairs with congenital toxoplasmosis in the mega-metropolis of the Valley of Mexico.

E. coli outbreak in a neonate intensive care unit in a general hospital in Mexico City

Nosocomial infections are a major cause of morbidity and mortality among neonates admitted to neonatal intensive care units (NICUs). The aim of this paper was to describe an outbreak of Escherichia coli among infants admitted to the NICU of the General Hospital "Dr. Manuel Gea Gonzalez" in May of 2008. The isolated E. coli strains were identified using standard biochemical methods. The susceptibilities of these strains were analysed by determining their minimal inhibitory concentrations. Following this, their molecular relationships to each other were assessed by pulsed field gel electrophoresis (PFGE) analysis and corroborated by serology. Twelve E. coli strains were isolated from blood, urine, or indwelling catheter samples from five cases of preterm infants within a 3-day period. Patients were admitted to the NICU of the general hospital and, during the outbreak, developed sepsis caused by E. coli. For four of the patients, the average age was 23 days, while one patient was a 3-month-old infant. Prior to sepsis, the infants had received assisted ventilation and hyperalimentation through a central venous catheter. Two profiles were observed by PFGE; profile A was identified as the outbreak's cause and an outcome of cross-infection, while profile B showed genetic differences but serologically it was identified as part of the same serotype. We conclude that E. coli colonised the patients through horizontal transmission. A focal source of the microorganism in this outbreak was not identified, but cross-transmission through handling was the most probable route.

Immunogenicity, reactogenicity and safety of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in Mexican infants

The immunogenicity and safety of the 10-valent pneumococcal conjugate vaccine, PHiD-CV, have been documented in European and Asian studies. In this open study conducted in Mexico (NCT00489554), 230 healthy infants received three doses of PHiD-CV and DTPa-HBV-IPV/Hib vaccines at 2, 4 and 6 months of age and two doses of oral human rotavirus vaccine at 2 and 4 months. Serotype-specific pneumococcal responses and opsonophagocytic activity (OPA) were measured one month post-dose 3. PHiD-CV's primary vaccination course was highly immunogenic against each of the 10 pneumococcal vaccine serotypes and carrier protein D. Antibody responses against pneumococcal serotypes and protein D were generally higher in Mexican infants compared with European antibody responses, and functional OPA responses were also higher or in the same range. The most frequent solicited local symptom was pain, with high but similar incidences of grade 3 pain reported at both injection sites (up to 15% of all doses). PHiD-CV was well tolerated, with no serious adverse events considered as causally related to vaccination. Most solicited symptoms were mild and there was no increase in incidence of solicited symptoms with successive vaccine doses.